Topic: Tag alias: webp -> invalid_tag

The tag alias #82168 webp -> invalid_tag is pending approval.

Reason: File format is automatically searchable without adding any tags (type:webp).
It had two uses, which I removed.

We also need to get rid of webm while we're at it

We could probably alias both webm and mp4 to animated without much hassle

The site currently still adds webm automatically, but assuming we alias it to a tag that should be right in 99% of cases it doesn't matter too much

The bulk update request #13541 is pending approval.

create alias webm (100606) -> animated (196895) # has blocking transitive relationships, cannot be applied through bur
create alias mp4 (0) -> animated (196895)

Reason: Unaliased in topic #26644, we have filetype searches and do not need these tags

From the sounds of it these tags existed due to heavy restrictions on metatags in searches, but most if not all of those have been resolved

This alias should be accurate in 99% of cases, the few slideshow posts shouldn't warrant a different target (and if they do we should talk about retargeting the gif alias)

The BTR is topic #54476, an implication to animated which is objectively incorrect regardless of the future status of the tag